Crocanthemum rosmarinifolium |
Crocanthemum bicknellii |
|
---|---|---|
rosemary frostweed |
hoary frostweed, plains frostweed |
|
Habit | Herbs. | Herbs. |
Stems | ascending to erect, (13–)20–40(–51) cm, stellate-tomentose. |
erect, clustered on vertical caudex, (12–)20–50(–67) cm, simple or branched, stellate-pubescent to stellate-tomentose. |
Leaves | cauline and, sometimes, basal basal mat-forming; petiole 1–3 mm; blade obovate, 10–22 × 3–5 mm; cauline: petiole 1–4 mm; blade oblanceolate to narrowly lanceolate, 10–38(–48) × 2–5.5(–7.8) mm, margins revolute; surfaces stellate-tomentose abaxially, stellate-pubescent adaxially, without simple hairs; lateral veins obscure abaxially. |
cauline; petiole 1–4 mm; blade narrowly elliptic to oblanceolate, (10–)18–32(–40) × 4–7(–10) mm, surfaces stellate-tomentose abaxially, stellate-pubescent adaxially, without simple hairs, lateral veins raised abaxially. |
Inflorescences | axillary and terminal, solitary flowers or glomerules; chasmogamous flowers solitary, at tips of branches, overtopping cleistogamous, cleistogamous 2–7 per glomerule, flowering 1–3 months later than chasmogamous. |
terminal, cymes; chasmogamous flowers 6–10(–18) per cyme; cleistogamous in glomerules, 1–10 flowers per glomerule, on lateral leafy branches 2.5–6 cm, flowering 1–3 months later than chasmogamous. |
Pedicels | 10–22 mm; bracts 3–7 × 0.5–1 mm. |
(1.5–)3–8(–12) mm; bracts 3–7 × 0.5–1 mm. |
Chasmogamous | flowers: outer sepals linear, 1.2–2.5 × 0.2 mm, inner sepals 2.5–4.3 × 1.3–2 mm, apex acute; petals obovate, 4–6 × 3.5–5 mm; capsules 2–3 × 1.4–1.8 mm, glabrous. |
flowers: outer sepals linear, 3.5–4.5(–8) × 0.4–1 mm, inner sepals ovate-elliptic, 5–8 × 2.4–4 mm, apex acute; petals obovate, 8–12 × 5–10 mm; capsules 3–5.5 × 2.5–4.5 mm, glabrous. |
Cleistogamous | flowers: outer sepals linear, 0.5–1 × 0.2 mm, inner sepals ovate, 1.5–1.8 × 1–1.5 mm, apex acute; capsules 1.3–1.7 × 1–1.3 mm, glabrous. |
flowers: outer sepals linear, 0.5–1.5 × 0.3 mm, inner sepals ovate-elliptic, 1.7–2.8 × 1.5–2.3 mm, apex acute capsules 1.5–2.2 × 1.2–2.2 mm, glabrous. |
Crocanthemum rosmarinifolium |
Crocanthemum bicknellii |
|
Phenology | Flowering May–Jul. | Flowering Jun–Jul. |
Habitat | Dry, sandy roadsides, openings in pine and pine-oak woodlands, disturbed soil of clearings and fields | Sandy or rocky barrens, glades, sandhills, prairies, fields, pine-oak woodlands, oak-hickory woodlands, montane outcrops and balds |
Elevation | 0–200 m (0–700 ft) | 0–1500 m (0–4900 ft) |
Distribution |
AL; AR; FL; GA; LA; MS; NC; OK; SC; TX; West Indies (Dominican Republic) |
AR; CO; CT; DE; GA; IA; IL; IN; KS; KY; MA; MD; ME; MI; MN; MO; NC; NE; NH; NJ; NY; OH; PA; RI; SC; SD; TN; VA; VT; WI; WV; WY; MB; ON |
Discussion | Crocanthemum rosmarinifolium is easily distinguished from sympatric species by its slender leaves, relatively small petaliferous flowers, occasional basal leaves, and overall pale color. As noted by R. M. Harper over a century ago, it seems not to occupy natural habitats and is found primarily on roadsides. Populations in the Dominican Republic occur up to at least 2200 m. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
The dense, often crowded, cleistogamous flowers on branches of Crocanthemum bicknellii late in the season contrast strongly with the relatively few, terminal, petaliferous flowers early in the season. Its closest relative is 12. C. propinquum; see that treatment for identification aids. The names C. majus (Linnaeus) Britton and Helianthemum majus (Linnaeus) Bicknell have been misapplied to C. bicknellii. They were based on Lechea major Linnaeus, which is a synonym of C. canadense, based on types. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 6, p. 407. | FNA vol. 6, p. 402. |
Parent taxa | Cistaceae > Crocanthemum | Cistaceae > Crocanthemum |
Sibling taxa | ||
Synonyms | Helianthemum rosmarinifolium, C. domingense, C. stenophyllum | Helianthemum bicknellii, H. canadense var. walkerae |
Name authority | (Pursh) Janchen: in H. G. A. Engler et al., Nat. Pflanzenfam. ed. 2, 21: 307. (1925) | (Fernald) Janchen: in H. G. A. Engler et al., Nat. Pflanzenfam. ed. 2, 21: 307. (1925) |
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